JPH11287176A - Abnormal pressure generation prevention device for hydraulic machinery - Google Patents

Abstract

(57) [Problem] To prevent the occurrence of abnormal pressure rise occurring in a suction pipe at the time of load interruption. In a hydraulic machine such as a water wheel or a pump water wheel,
A water pressure detector 13 for detecting the water pressure at the center of the suction pipe 8,
Temperature detector 10 for detecting the temperature of water flowing through the suction pipe 8
0 and the water pressure and temperature detection signals detected by the water pressure detector 13 and the temperature detector 100 are input, and the pressure at the center of the suction pipe 8 is determined based on the temperature detection signal.
It is determined whether or not the saturated vapor pressure in the suction pipe has been reached, and on the condition that the pressure at the center of the suction pipe has reached the saturated vapor pressure in the suction pipe at that time, the closing speed of the guide vane 4 is reduced to reduce the water. A control device 14 is provided for performing a control for weakening the hammering action and returning to the original closing speed when the pressure is restored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing abnormal pressure generation of a hydraulic machine such as a water turbine and a pump turbine.

[0002]

2. Description of the Related Art In a power plant that generates electric power by a hydraulic machine such as a water turbine or a pump turbine, a drainage channel is required to prevent an abnormally high pressure from being generated in a suction pipe due to a water hammer effect at the time of load interruption. Also has a surge tank, and is installed much lower than the lower pond with a large margin.
For this reason, excavating deep underground requires huge civil engineering costs.

Here, the water hammer phenomenon will be described with reference to FIG. FIG. 10 shows a cross section of the pump turbine. In FIG. 10, reference numeral 1 denotes a main shaft of a water turbine. A generator motor 2 is connected to an upper end of the main shaft 1, and a runner 3 is attached to a lower end of the main shaft 1.

A casing 6 is provided radially outside the runner 3 via a guide vane 4 and a stay vane 5, and the casing 6 is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3, and the suction pipe 8 is connected to a lower pond (not shown) via a water discharge passage 9. In the middle of the water discharge channel 9, a surging tank 11 is provided to reduce surging (water hammer).
Is provided. On the other hand, the opening of the guide vane 4 is adjusted by the governor 10.

[0006]

In the pumped-storage power plant constructed as described above, if the load is interrupted during operation of the generator due to a trouble in the power transmission system, the rotation of the generator increases and the pressure increases accordingly. As it rises, to prevent this,
The guide vane 4 is suddenly closed by a command given to the governor 10. Then, by the water hammer action, the suction pipe 8
, The water hammer is eased because water is supplied from the surge tank 11. However, the construction of this surge tank requires huge civil engineering construction costs.

[0007] In a pumped-storage power plant in which the surge tank is omitted, if the load is cut off due to a trouble in the power transmission system during operation of the generator, the generator will rotate and the pressure will increase accordingly, thus preventing this. The guide vanes 3 are suddenly closed. Then, the pressure of the suction pipe 8 rapidly drops due to the water hammer action, and when the pressure in the suction pipe 8 becomes equal to or lower than the saturated atmospheric pressure,
The inside of the suction pipe 8 is hollowed out, that is, separated in water. When the pressure wave is reflected and returned at the outlet of the water discharge channel due to the water hammer action, the separated water column is recombined to cause an abnormal increase in pressure such that the suction pipe 8 is damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent the occurrence of an abnormal pressure rise that occurs in a suction pipe when a load is cut off, thereby omitting a surge tank, and as much as possible. An object of the present invention is to provide an apparatus for preventing abnormal pressure generation of a hydraulic machine that can be an economical power plant that can be installed in a shallow underground.

[0009]

In order to achieve the above object, an apparatus for preventing abnormal pressure generation of a hydraulic machine is constituted by the following means. According to a first aspect of the present invention, a main engine is connected to one end of a main shaft, a runner is attached to the other end, and a casing is provided radially outward of the runner via a guide vane and a stay vane, and is provided below the runner. In a hydraulic machine such as a water turbine or a pump turbine provided with a suction pipe, a water pressure detection means for detecting a water pressure in a central portion of the suction pipe, a temperature detection means for detecting a temperature of water flowing in the suction pipe, The water pressure and temperature detection signals detected by the water pressure detection means and the temperature detection means are inputted, and it is determined whether or not the pressure at the center of the suction pipe has reached the saturated vapor pressure in the suction pipe determined based on the temperature detection signal. When the determination means determines that the pressure at the center of the suction pipe has reached the saturated vapor pressure in the suction pipe at that time, Slows the closure rate of Doben weaken the water hammer by, and a control means pressure control back to the original closing speed Once recovered.

In the apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described structure, the pressure at the center of the suction pipe and the temperature of the water flowing through the suction pipe are detected, and the pressure in the suction pipe is equal to or lower than the saturated vapor pressure. Detecting the occurrence of underwater separation by lowering the speed, reducing the guide vane closing speed and weakening the water hammer action,
When the pressure is recovered, the control is performed to return to the original closing speed, whereby occurrence of abnormal pressure can be prevented.

According to a second aspect of the present invention, a main engine is connected to one end of a main shaft, and a runner is attached to the other end.
In a hydraulic machine such as a water turbine or a pump turbine in which a casing is provided radially outward of the runner via guide vanes and stay vanes and a suction pipe is provided below the runner, the water pressure of the wall of the suction pipe is detected. Water pressure detecting means, a temperature detecting means for detecting a temperature of water flowing in the suction pipe to obtain a saturated vapor pressure, a rotational speed detecting means for detecting a rotational speed of the main engine and obtaining an outer peripheral speed of a runner outlet portion, The water pressure, saturated vapor pressure, and rotation speed detection signals detected by the respective detecting means are input, and the following equation: ha ≧ hd + k (Ue ² / 2g) where ha: saturated vapor pressure in the suction pipe hd: pressure on the suction pipe wall Ue: Outer peripheral speed of runner outlet g: Gravitational acceleration k: Determination means for determining that underwater separation has occurred when the pressure distribution coefficient (-0.05 to -0.07) is satisfied. When water separation is determined to have occurred by determining means, said guide at slow closing speed of the vane weakened water hammer, and a control means pressure control back to the original closing speed Once recovered.

In the apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described structure, the pressure in the suction pipe wall, the water temperature in the suction pipe, and the rotation speed of the main engine are detected, and the pressure in the suction pipe is changed to the saturated steam. When the pressure drops below the pressure, the occurrence of underwater separation is detected, and the guide vane closing speed is slowed to weaken the water hammer effect, and when the pressure is restored, control is returned to the original closing speed to prevent the occurrence of abnormal pressure. can do.

According to a third aspect of the present invention, a main engine is connected to one end of a main shaft, and a runner is attached to the other end.
Vibration detecting means for detecting vibration of the runner in a hydraulic machine such as a water turbine or a pump turbine provided with a casing via guide vanes and stay vanes radially outward of the runner and provided with a suction pipe below the runner. When,
Determining means for receiving a vibration detection signal detected by the vibration detecting means and determining that underwater separation has occurred when the vibration level of the runner does not reach a predetermined level after the load is interrupted; and When the determining means determines that underwater separation has occurred, the control means controls the closing speed of the guide vane to reduce the water hammer action, and performs control to return to the original closing speed when the pressure is restored.

In the apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described configuration, runner vibration is detected, and since the vibration is below a predetermined level, occurrence of underwater separation is detected, and the guide vane is closed. By reducing the speed to reduce the water hammer effect and performing control to return to the original closing speed when the pressure recovers, it is possible to prevent the occurrence of abnormal pressure.

According to a fourth aspect of the present invention, a main engine is connected to one end of a main shaft, and a runner is attached to the other end.
In a hydraulic machine such as a water turbine or a pump turbine in which a casing is provided via guide vanes and stay vanes radially outward of the runner and a suction pipe is provided below the runner, the water pressure at the center of the suction pipe is detected. Pressure detection means, a temperature detection means for detecting the temperature of the water flowing in the suction pipe, and a water pressure and temperature detection signal detected by the water pressure detection means and the temperature detection means are inputted, and the pressure at the center of the suction pipe is reduced. Determining means for determining whether or not the saturated vapor pressure in the suction pipe determined based on the temperature detection signal has been reached; and, by this determining means, the pressure at the center of the suction pipe is reduced to the saturated vapor pressure in the suction pipe at that time. When it is determined that the pressure has reached, the control means supplies air to the suction pipe having a reduced pressure and supplies high-pressure water from the iron pipe via a bypass valve. Equipped with a.

In the apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described structure, the pressure at the center of the suction pipe and the temperature of the water flowing through the suction pipe are detected, and the pressure in the suction pipe is equal to or lower than the saturated vapor pressure. As a result, water column separation is detected and air is supplied to the suction pipe with reduced pressure, and high-pressure water is also supplied from the iron pipe via the bypass valve, facilitating the recovery of pressure in the suction pipe. Thus, occurrence of abnormal pressure can be prevented.

According to a fifth aspect of the present invention, a main engine is connected to one end of a main shaft, and a runner is attached to the other end.
In a hydraulic machine such as a water turbine or a pump turbine in which a casing is provided radially outward of the runner via guide vanes and stay vanes and a suction pipe is provided below the runner, the water pressure of the wall of the suction pipe is detected. Water pressure detecting means, a temperature detecting means for detecting a temperature of water flowing in the suction pipe to obtain a saturated vapor pressure, a rotational speed detecting means for detecting a rotational speed of the main engine and obtaining an outer peripheral speed of a runner outlet portion, The water pressure, saturated vapor pressure, and rotation speed detection signals detected by the respective detecting means are input, and the following equation: ha ≧ hd + k (Ue ² / 2g) where ha: saturated vapor pressure in the suction pipe hd: pressure on the suction pipe wall Ue: Outer peripheral speed of runner outlet g: Gravitational acceleration k: Determination means for determining that underwater separation has occurred when the pressure distribution coefficient (-0.05 to -0.07) is satisfied. Comprising the water separation is determined to have occurred by determining means and supplying air to the draft tube where the pressure is reduced, and control means for supplying a high-pressure water via the bypass valve from the iron tube.

In the apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described structure, the pressure in the suction pipe wall, the water temperature in the suction pipe and the rotation speed of the main engine are detected, and the pressure in the suction pipe is reduced. The occurrence of underwater separation is detected when the pressure drops below the saturated vapor pressure, and the air is sucked into the suction pipe whose pressure has dropped, and high-pressure water is also supplied from the iron pipe via a bypass valve. Recovery is promoted, and occurrence of abnormal pressure can be prevented.

According to a sixth aspect of the present invention, a main unit is connected to one end of a main shaft, and a runner is attached to the other end.
Vibration detecting means for detecting vibration of the runner in a hydraulic machine such as a water turbine or a pump turbine provided with a casing via guide vanes and stay vanes radially outward of the runner and provided with a suction pipe below the runner. When,
Determining means for receiving a vibration detection signal detected by the vibration detecting means and determining that underwater separation has occurred when the vibration level of the runner does not reach a predetermined level after the load is interrupted; and When the determination means determines that underwater separation has occurred, the control means supplies air to the suction pipe having a reduced pressure and supplies high-pressure water from the iron pipe via a bypass valve.

The apparatus for preventing abnormal pressure generation of a hydraulic machine having the above-described configuration detects runner vibration and detects the occurrence of water column separation because the vibration is below a predetermined level. Since the high-pressure water is supplied from the iron pipe via the bypass valve while the air is sucked into the lowered suction pipe, the recovery of the pressure in the suction pipe is promoted, and the occurrence of abnormal pressure can be prevented.

According to a seventh aspect of the present invention, in the apparatus for preventing abnormal pressure from being generated in a hydraulic machine according to any one of the fourth to sixth aspects, water is supplied to the suction pipe having a reduced pressure. The direction in which the high-pressure water blows is opposite to the rotation of the runner.

In the apparatus for preventing abnormal pressure from being generated in a hydraulic machine having the above-mentioned structure, the invention according to any one of claims 4 to 6 is characterized in that high-pressure water is supplied to the suction pipe. Water is injected into the suction pipe with the direction opposite to the rotation direction, and the component in the turning direction in the suction pipe is canceled, so that a pressure drop at the center of the suction pipe can be suppressed, and occurrence of abnormal pressure can be prevented. .

According to an eighth aspect of the present invention, in the apparatus for preventing abnormal pressure from occurring in a hydraulic machine according to the third or sixth aspect, the vibration detecting means of the runner is an acoustic emission sensor.

In the apparatus for preventing abnormal pressure from occurring in a hydraulic machine having the above-described structure, in the invention according to claim 3 or 6, the vibration detecting means of the runner is an acoustic emission sensor. Vibration of the runner can be detected accurately.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an abnormality prevention device for a hydraulic machine according to a first embodiment of the present invention.
The same parts as in FIG.

In FIG. 1, reference numeral 1 denotes a main shaft of a water turbine, and a generator motor 2 is connected to an upper end of the main shaft 1;
A runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5.
Is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3 and is connected to a lower pond (not shown) via a water discharge passage 9. A water pipe 12 is provided above the suction pipe 8 to measure the pressure at the center of the suction pipe 8, and a water pressure detector 13 provided in the water pipe 12 detects a water pressure, and detects this by an electric signal. And is led to the controller 14. A temperature detector 100 for detecting the temperature of the water in the suction pipe 8 is provided above the suction pipe 8, and the detection signal is converted into a saturated vapor pressure of the water in the suction pipe 8 by a thermometer 101. It is led to the control device 14.

On the other hand, the opening degree of the guide vane is controlled by the control device 14.
The speed is controlled by the governor 10 which operates according to a command from the controller. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 3 is the governor 1
It is suddenly closed by a command given to 0. Then, the pressure of the suction pipe 8 is reduced by the water hammer action.

In such a state, the pressure is transmitted to the water pressure detector 13 via the water guide pipe 12, and the pressure at the center of the suction pipe 8 detected by the water pressure detector 13 and the thermometer detected by the temperature detector 100 Suction tube 8 converted in 101
The controller 14 compares the saturated vapor pressure of the water in the suction pipe 8 obtained from the water temperature in the suction pipe with the controller 14.
A command is issued to the governor 10 so that the guide vane closing speed is slower than the normal speed as shown by the broken line in FIG. Then, when the pressure in the suction pipe 8 recovers and becomes equal to or higher than the saturated vapor pressure, the normal closing speed is returned.

In FIG. 2, a is a guide vane closing start point, b is an underwater separation occurrence point, and c is a pressure recovery point. As described above, according to the present embodiment, the lowest pressure in the center of the suction pipe 8 due to the swirling flow generated by the runner 3 is directly detected in the suction pipe 8, so that the occurrence of underwater separation can be detected accurately. Since the guide vanes 6 can be controlled so as to suppress water hammer based on this, the occurrence of abnormal pressure can be prevented.

FIG. 3 is a block diagram of an apparatus for preventing abnormality of a hydraulic machine according to a second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals. In FIG. 1, 1
Denotes a main shaft of a water turbine, a generator motor 2 is connected to an upper end of the main shaft 1, and a runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5, and the casing 6 is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3 and is connected to a lower pond (not shown) via a water discharge passage 9. A water pipe 15 for measuring the pressure hd of the pipe wall of the suction pipe 8 is provided above the suction pipe 8, and a water pressure h is detected by a water pressure detector 13 provided in the water pipe 15.
d is detected, the detection signal is converted into an electric signal, and is guided to the control device 14.

A temperature detector 100 for detecting the temperature of water in the suction pipe 8 is provided above the suction pipe 8.
The detection signal is converted into a saturated vapor pressure ha of water in the suction pipe 8 by the thermometer 101, and is guided to the control device 14. Further, the rotation speed of the generator motor 2 is detected by a rotation speed detector 16, and the rotation speed is adjusted by a rotation speed converter 17 and input to the control device 14 as a runner outlet outer peripheral speed Ue.

On the other hand, the opening degree of the guide vane is controlled by the control device 14.
The speed is controlled by the governor 10 which operates according to a command from the controller. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 3 is the governor 1
It is suddenly closed by a command given to 0. Then, the pressure of the suction pipe 8 is reduced by the water hammer action.

In this state, the control unit 14 transmits the pressure hd of the pipe wall of the suction pipe 8 detected by the water pressure detector 13 to the water pressure detector 13 via the water guide pipe 12 and the rotation speed detection. Using the rotation speed Ue detected by the heater 16 and adjusted by the rotation speed converter 17, the pressure at the center of the suction pipe 8 determined by the equation (1) is detected by the temperature detector 100 and converted by the thermometer. Saturated vapor pressure hd of water in the suction pipe 8 determined from the water temperature in the suction pipe 8
Is compared to

Here, the pressure at the center of the suction pipe 8 is ha ≧ hd + k (Ue ² / 2g) (1) where ha: saturated vapor pressure in the suction pipe hd: pressure on the suction pipe wall Ue: runner Outer peripheral speed g: gravitational acceleration k: pressure distribution coefficient If the above comparison result is equal to or lower than the saturated vapor pressure, the controller 14
A command is issued to the governor 10 to slow down the guide vane closing speed as shown by the broken line in FIG. 2, and when the pressure in the suction pipe 8 recovers and becomes higher than the saturated vapor pressure, the speed is returned to the original closing speed. It is.

Incidentally, the pressure distribution coefficient k in the equation (1) slightly changes depending on the guide vane opening, and as shown in FIG.
~ -0.07 is obtained.

As described above, according to the present embodiment, the pressure at the center of the suction pipe 8 which is lowest in the suction pipe 8 due to the swirling flow generated by the runner 3 is obtained based on the experimental results, so that it is accurate. The occurrence of underwater separation can be detected. In addition, the guide vanes 6
Can be controlled and the water pressure is detected by the pipe wall,
The occurrence of abnormal pressure can be prevented with high reliability without disturbing the internal flow and without fear of falling off of the water pipe support material.

In the above embodiment, the calculation of the saturated vapor pressure by the thermometer 101 has been described. However, it is also possible to provide the controller 14 with the calculation function. FIG. 5 is a configuration diagram of an abnormality prevention device for a hydraulic machine according to a third embodiment of the present invention, and the same parts as those in FIG.

In FIG. 5, reference numeral 1 denotes a main shaft of a water turbine, and a generator motor 2 is connected to an upper end of the main shaft 1;
A runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5.
Is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3 and is connected to a lower pond (not shown) via a water discharge passage 9. The vibration detector 1 attached below the main shaft 1
8 is the runner vibration signal detected by the FM telemeter 1
9, the transmission is adjusted to the vibration transducer 20, and the control device 1
It is led to 4.

On the other hand, the opening degree of the guide vane
The speed is controlled by the governor 10 which operates according to a command from the controller. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 4 is the governor 1
It is suddenly closed by a command given to 0. Then, the pressure of the suction pipe 8 is reduced by the water hammer action. Then, when an underwater separation phenomenon occurs, in which water and air in the suction pipe 8 are separated due to a decrease in pressure, water does not exist around the runner 3 and the disturbance of the runner 3 decreases as the disturbance decreases.

In such a state, the vibration of the runner 3 is detected by the vibration detector 18 and sent to the vibration converter 20 via the FM telemeter 19, and the vibration adjusted by the vibration converter 20 is transmitted to the controller 14 And compared with the vibration level at the limit of occurrence of underwater separation. When it is determined that underwater separation has occurred, the control device 14 controls the governor 1 to reduce the guide vane closing speed from the normal speed as shown in FIG.
A command is issued at zero. Then, when the vibration level of the runner 3 becomes higher than the underwater separation occurrence limit, it is returned to the original normal closing speed. As a result, occurrence of abnormal pressure is prevented.

FIG. 6 is a block diagram of an apparatus for preventing occurrence of abnormality in a hydraulic machine according to a fourth embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals. In FIG. 6, 1
Denotes a main shaft of a water turbine, a generator motor 2 is connected to an upper end of the main shaft 1, and a runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5, and the casing 6 is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3, and is connected to a lower pond (not shown) via a water discharge passage 9. A water guide pipe 12 for measuring the pressure at the center of the suction pipe 8 is provided above the suction pipe 8, the water pressure is detected by a water pressure detector 13, and the water pressure is converted into an electric signal, which is transmitted to a control device 14. Be guided.

A temperature detector 100 for detecting the temperature of water in the suction pipe 8 is provided above the suction pipe 8.
The detection signal is converted into a saturated vapor pressure of water in the suction pipe 8 by the thermometer 101, and is guided to the control device 14. Further, an upper part of the suction pipe 8 is connected to a supply pipe 21 having one end connected to a high-pressure air tank (not shown) via a supply valve 22 operated by the control device 14, and a water supply pipe 23 from the casing 6 via a water supply valve 24. Are each open.

On the other hand, the opening degree of the guide vane 4
The speed is controlled by the governor 10 which operates according to the command from the control unit 4. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 4 is rapidly closed by a command given from the control device 14 to the governor 10. Then, the pressure of the suction pipe 8 is reduced by the water hammer action.

In such a state, the pressure at the center of the suction pipe 8 transmitted to the water pressure detector 13 via the water pipe 12 and detected is detected by the temperature detector 100 and
The value is compared with the saturated vapor pressure of the water in the suction pipe 8 obtained from the water temperature in the suction pipe 8 converted in step 01. If the pressure is equal to or lower than the saturated vapor pressure, the controller 14 sends the air supply valve 22
Then, an open command is issued to the water supply valve 24, and both valves are opened, high-pressure air and high-pressure water are injected into the suction pipe 8, and
Pressure is restored. Then, when the pressure becomes equal to or higher than the saturated vapor pressure, a closing command is issued from the control device 14 to the air supply valve 22 and the water supply valve 24, both valves are closed, and the injection of high-pressure air and high-pressure water is stopped.

According to the present embodiment, the lowest pressure in the central portion of the suction pipe 8 is directly detected due to the swirling flow generated by the runner 3 in the suction pipe 8, so that the occurrence of underwater separation is detected with high accuracy. Based on this, the pressure of the suction pipe 8 can be adjusted so as to suppress water hammer, and as a result, occurrence of abnormal pressure can be prevented.

FIG. 7 is a block diagram of an apparatus for preventing occurrence of abnormality in a hydraulic machine according to a fifth embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals. In FIG. 7, 1
Denotes a main shaft of a water turbine, a generator motor 2 is connected to an upper end of the main shaft 1, and a runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5, and the casing 6 is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3, and is connected to a lower pond (not shown) via a water discharge channel 9. A water pipe 15 for measuring the pressure of the pipe wall of the suction pipe 8 is provided on the upper part of the suction pipe 8, and the water pressure is detected by a water pressure detector 13 connected to the water pipe 15 and the water pressure is detected. The signal is converted into a signal and guided to the control device 14.

A temperature detector 100 for detecting the temperature of water in the suction pipe 8 is provided above the suction pipe 8.
The detection signal is converted into a saturated vapor pressure of water in the suction pipe 8 by the thermometer 101, and is guided to the control device 14.

On the other hand, the opening degree of the guide vane
The speed is controlled by the governor 10 which operates according to a command from the controller. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 4 is rapidly closed by a command given from the control device 14 to the governor 10. Then, the pressure of the suction pipe 8 is reduced by the water hammer action.

In such a state, the pressure hd of the pipe wall of the suction pipe 8 detected and transmitted to the water pressure detector 13 via the water conduit 15 and the rotation speed converter detected and detected by the rotation speed detector 16 are used. Using the runner outlet peripheral speed Ue obtained from the adjusted rotation speed, the pressure at the center of the suction pipe 8 obtained by the above equation (1) is obtained by converting the detection signal detected by the temperature detector 100 into the temperature. Is compared with the saturated vapor pressure ha of the water in the suction pipe 8 converted by the
If the pressure is equal to or higher than the saturated vapor pressure, the control device 14 sends the air supply valve 2
An opening command is issued to the water supply valve 2 and the water supply valve 24, and both valves are opened, high-pressure air and high-pressure water are injected into the suction pipe 8, and the pressure is restored.

When the pressure exceeds the saturated vapor pressure, the controller 14 issues a close command to the air supply valve 22 and the water supply valve 24, and both valves are closed to stop the injection of high-pressure air and high-pressure water.

According to the present embodiment, the lowest pressure in the center of the suction pipe 8 is obtained based on the experimental results because of the swirling flow generated by the runner 3 in the suction pipe 8, so that the water pressure is accurately determined. The occurrence of separation can be detected, and based on this, the pressure of the suction pipe 8 can be adjusted to suppress water hammer, and as a result, the occurrence of abnormal pressure can be prevented.

FIG. 8 is a block diagram of an apparatus for preventing abnormality of a hydraulic machine according to a sixth embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals. In FIG. 8, 1
Denotes a main shaft of a water turbine, a generator motor 2 is connected to an upper end of the main shaft 1, and a runner 3 is attached to a lower end of the main shaft 1. A casing 6 is provided radially outward of the runner 3 via a guide vane 4 and a stay vane 5, and the casing 6 is connected to an upper pond (not shown) via an iron pipe 7.

A suction pipe 8 is provided below the runner 3, and the suction pipe 8 is connected to a lower pond (not shown) via a water discharge passage 9. The runner vibration detection signal of the vibration detector 18 attached below the main shaft 1 is transmitted to the vibration detector 20 by the FM telemeter 19, and the vibration detection signal adjusted by the vibration detector 20 is transmitted to the control device 1
It is led to 4.

On the other hand, the degree of opening of the guide vanes is adjusted by the governor 10. In the pumped-storage power plant configured as described above, if load interruption occurs due to a trouble in the power transmission system during operation of the generator, the rotation of the generator increases, and the guide vanes 4 is suddenly closed by a command given to the governor 10. Then, the pressure of the suction pipe 8 is reduced by the water hammer action. When the underwater separation phenomenon occurs, the runner 3
There is no water around and runner 3
Vibration also decreases.

In such a state, the vibration of the runner 3 is detected by the vibration detector 18, sent to the vibration converter 20 via the FM telemeter 19, and the vibration adjusted by the vibration converter 20 is transmitted to the controller 14. And compared with the vibration level at the limit of occurrence of underwater separation. When it is determined that underwater separation has occurred, the control device 14 issues an open command to the air supply valve 22 and the water supply valve 24, and both valves are opened, high-pressure air and high-pressure water are injected into the suction pipe 8, and the pressure is restored. .

When the vibration level of the runner 3 becomes higher than the underwater separation occurrence limit, the controller 14
2 and the water supply valve 24 are closed, both valves are closed and injection of high-pressure air and high-pressure water is stopped. As a result,
The occurrence of abnormal pressure can be prevented.

FIG. 9 is a cross-sectional view of a suction pipe 8 of an apparatus for preventing abnormality of a hydraulic machine according to a seventh embodiment of the present invention. A connecting portion is shown, in which high-pressure air and high-pressure water are injected in a direction opposite to the rotational direction of the runner 3. Therefore, there is an effect that the swirling flow in the suction pipe 8 is suppressed and a pressure drop in the central portion is prevented.

The configuration of the abnormal pressure preventing device for a hydraulic machine according to the eighth embodiment uses an AE (acoustic emission) detector as the vibration detector 18 in the third and sixth embodiments. This is effective in detecting vibration in a high frequency region generated in an operation state in which cavitation occurs. The operating state in which cavitation occurs is exactly this state, so that the operating state can be promoted with higher sensitivity, and the reliability of the abnormal pressure generation preventing device can be improved.

[0064]

As described above, according to the present invention, a surge tank can be omitted, and even in an economical power plant that can be installed underground as shallow as possible, an abnormal pressure rise generated in the suction pipe when the load is cut off. It is possible to provide an abnormal pressure generation prevention device for a hydraulic machine that can prevent generation of water.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 2 is a view for explaining a guide vane closing method in the embodiment.

FIG. 3 is a configuration diagram showing a second embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 4 is a diagram showing a pressure distribution coefficient with respect to a radial position in the suction pipe in the embodiment.

FIG. 5 is a configuration diagram showing a third embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 6 is a configuration diagram showing a fourth embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 7 is a configuration diagram showing a fifth embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 8 is a configuration diagram showing a sixth embodiment of an abnormal pressure generation preventing device for a hydraulic machine according to the present invention.

FIG. 9 is a cross-sectional view showing a suction pipe section in a seventh embodiment of the apparatus for preventing abnormal pressure from occurring in a hydraulic machine according to the present invention.

FIG. 10 is a configuration explanatory view showing an example of a pump turbine as a conventional hydraulic machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Spindle 2 ... Generator motor 3 ... Runner 4 ... Guide vane 5 ... Stay vane 6 ... Casing 7 ... Iron pipe 8 ... Suction pipe 9 ... Drainage channel 10 ... Governor 11 ... Surge Tank 12 Water pipe 13 Water pressure detector 14 Controller 15 Water pipe 16 Rotation detector 17 Rotation speed 18 Vibration detector 19 FM telemeter 20 Vibration converter 21 ... air supply pipe 22 ... air supply valve 23 ... water supply pipe 24 ... water supply valve 100 ... temperature detector 101 ... thermometer

Claims (8)

[Claims] A main machine is connected to one end of a main shaft, a runner is attached to the other end, a casing is provided radially outside the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a water wheel or a pump water wheel provided, a water pressure detecting means for detecting a water pressure at a central portion of the suction pipe, a temperature detecting means for detecting a temperature of water flowing in the suction pipe, Determining means for receiving the water pressure and the temperature detection signal detected by the temperature detection means and determining whether or not the pressure at the center of the suction pipe has reached a saturated vapor pressure in the suction pipe determined based on the temperature detection signal; When the determination means determines that the pressure at the center of the suction pipe has reached the saturated vapor pressure in the suction pipe at that time, Control means for slowing down the chain speed to reduce the water hammer effect and returning to the original closing speed when the pressure is restored, so as to prevent the occurrence of abnormal pressure, Abnormal pressure generation prevention device. 2. A main machine is connected to one end of the main shaft, a runner is attached to the other end, a casing is provided radially outward of the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a provided water wheel or a pump water wheel, a water pressure detecting means for detecting a water pressure of a wall portion of the suction pipe,
Temperature detecting means for detecting the temperature of water flowing in the suction pipe to obtain a saturated vapor pressure, rotational speed detecting means for detecting the rotational speed of the main engine to determine the outer peripheral speed of the runner outlet, and detection by each of these detecting means And the following equation: ha ≧ hd + k (Ue ² / 2g) where ha: saturated vapor pressure in the suction pipe hd: pressure on the wall of the suction pipe Ue: outer circumference of the runner outlet Velocity g: gravitational acceleration k: determination means for determining that underwater separation has occurred when the pressure distribution coefficient (-0.05 to -0.07) is satisfied, and when the determination means determines that underwater separation has occurred, Control means for slowing the closing speed of the guide vanes to reduce the water hammer effect and returning to the original closing speed when the pressure recovers is provided to prevent the occurrence of abnormal pressure. Abnormal pressure prevention device of the hydraulic machine to be. 3. A main machine is connected to one end of the main shaft, a runner is attached to the other end, a casing is provided radially outward of the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a water turbine or a pump turbine provided, a vibration detecting means for detecting the vibration of the runner and a vibration detection signal detected by the vibration detecting means are input, and the vibration of the runner causes a load interruption. A determining means for determining that underwater separation has occurred when the vibration level does not reach the predetermined level later, and when the determining means determines that underwater separation has occurred, the closing speed of the guide vane is reduced to reduce water. Control means for weakening the hammering action and performing control to return to the original closing speed when the pressure recovers, so as to prevent occurrence of abnormal pressure. Abnormal pressure prevention device of the hydraulic machine. 4. A main machine is connected to one end of the main shaft, a runner is attached to the other end, a casing is provided radially outward of the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a water wheel or a pump water wheel provided, a water pressure detecting means for detecting a water pressure at a central portion of the suction pipe, a temperature detecting means for detecting a temperature of water flowing in the suction pipe, Determining means for receiving the water pressure and the temperature detection signal detected by the temperature detection means and determining whether or not the pressure at the center of the suction pipe has reached a saturated vapor pressure in the suction pipe determined based on the temperature detection signal; When it is determined by the determining means that the pressure in the central portion of the suction pipe has reached the saturated vapor pressure in the suction pipe at that time, the pressure has decreased. While supply to out pipe, abnormal pressure prevention device of the hydraulic machine, characterized in that a control means for supplying high-pressure water via the bypass valve from the iron tube. 5. A main machine is connected to one end of the main shaft, a runner is attached to the other end, a casing is provided radially outward of the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a provided water wheel or a pump water wheel, a water pressure detecting means for detecting a water pressure of a wall portion of the suction pipe, a temperature detecting means for detecting a temperature of water flowing in the suction pipe and obtaining a saturated vapor pressure, A rotation speed detecting means for detecting a rotation speed of the main engine to obtain an outer peripheral speed of a runner outlet portion, and a water pressure, a saturated vapor pressure and a rotation speed detection signal detected by each of these detection means are inputted, and the following equation is used: ha ≧ hd + k ( ue ² / 2g) where, ha: saturated vapor pressure at suction tube hd: pressure suction pipe wall ue: runner outlet portion outer peripheral speed g: gravitational acceleration k: pressure distribution A judging means for judging that underwater separation has occurred when the number (-0.05 to -0.07) is satisfied; and when the judging means judges that underwater separation has occurred, supply to the suction pipe having a reduced pressure. And a control unit for supplying high-pressure water from a steel pipe via a bypass valve. 6. A main machine is connected to one end of the main shaft, a runner is attached to the other end, a casing is provided radially outward of the runner via guide vanes and stay vanes, and a suction pipe is provided below the runner. In a hydraulic machine such as a water turbine or a pump turbine provided, a vibration detecting means for detecting the vibration of the runner and a vibration detection signal detected by the vibration detecting means are input, and the vibration of the runner causes a load interruption. A determining means for determining that underwater separation has occurred when the vibration level does not reach the predetermined level later, and when the determining means determines that underwater separation has occurred, supplying air to the suction pipe having a reduced pressure. And a control means for supplying high-pressure water from an iron pipe via a bypass valve. 7. An apparatus for preventing abnormal pressure from occurring in a hydraulic machine according to any one of claims 4 to 6, wherein
An abnormal pressure generation prevention device for a hydraulic machine, characterized in that a direction in which high-pressure water is supplied to a suction pipe having a reduced pressure is blown in a direction opposite to a rotation of a runner. 8. The apparatus for preventing abnormal pressure generation of a hydraulic machine according to claim 3, wherein the vibration of the runner is detected by an acoustic emission sensor.